Exhaust manifold leak (issue)

[phlegm]

I hear a strange noise from the engine that a few of my shade trees and I at church have decided is a leak at the exhaust manifold. Before I tear it down I want to make sure there is not something easy that could be causing this that can be fixed without removing them.

From what I understand there is a thermostat type device that constricts the flow out of the exhaust in order to warm the engine up faster, and these devices are on both sides and can leak from the seals after a while.

Is this true? and should I check this first. any other obvious things to check? Just want to get as much Background as I can before I start digging in. Thanks in advance.

[jerry moss]

you should not have two heat risers, only one is normal. i work in a muffler shop and we also sell a block that replaces the heatriser. a lot of people make a mistake when they work on the exhaust manifolds and use gaskets between the manifold and the head, a guarnteed leak sooner or later. have the manifolds surfaced, clean the heads real good and bolt them up metal to metal, torque the bolts correctly for proper expansion and contraction and you'll not have anymore problems. if the studs at the flange end are iffy, nows the time to replace them too. if you have old style manifolds with the choke heat tube inside, those can burn through and create a leak also, if thats the case, you can have the choke tube holes welded closed before resurfacing. hope this helps.

[phlegm]

How hard are these to replace?

[jerry moss]

the only difficult part is the studs, depending on the amount of corrision. usually a little heat from a victor wrench will help.